Brushless dc drive mechanism for seld propelled aplicance

ABSTRACT

An upright cleaning device comprising, an actuator for receiving a user input, an upper assembly, a base assembly, a rear wheel mounted to the base assembly, configured to support the rear portion of the base assembly, and a drive mechanism located in the base assembly. The actuator is mounted to upper assembly, and the upper assembly is pivotally mounted to the base assembly. The drive mechanism has its major diameter in contact with a surface to be cleaned, and the drive mechanism is configured to operate at one of: full speed in one direction, no speed and full speed in the opposite direction, according to the relative position of the actuator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to home appliances. More particularly, thepresent invention relates to a self-propelled or power assist drivesystem for use in an upright cleaning device. One such device can be acarpet extractor. It is to be appreciated, however, that the presentinvention may find further application in other environments where it isadvantageous to controllably propel or assist cleaning devices, such asupright vacuum cleaners, and the like.

2. Discussion of the Art

Self-propelled upright vacuum cleaners are well known in the art.However, self-propelled carpet extractors are less well known. Thepreferred motion of a carpet extractor or wet extractor is of adifferent nature than the preferred motion of an upright vacuum cleanerand thus requires a specific solution for a power-assist drive systemfor the extractor that solves the moisture problems as well as the modeof operation associated with the nature of the wet extractor.Specifically, the operation of an upright vacuum cleaner ischaracterized by quick, short strokes compared to that of an extractor.The motion of an upright vacuum cleaner is further characterized bycontinuously variable acceleration and deceleration. In contrast, anextractor ideally operates at a continuous velocity optimized forextraction efficiency.

The similarities shared between the two cleaning devices may lead one toconclude that a drive system designed for an upright vacuum cleaner issuitable for use in a wet extractor. This, however, will lead tooperational problems if the vacuum cleaner drive is not adapted toaddress the distinct nature of the motion of a wet extractor.Specifically, the most popular drive systems used in upright vacuumcleaners today are mechanical friction clutches of some form. Theseclutches generally rely on some form of actuation force that is imposedmechanically, usually via a mechanical linkage from a reciprocatinghandle to a lever that forces the friction surfaces together, coupling adrive power source to an output such as a wheel. The amount of torquetransmitted between the drive power source and the output isproportional to the actuation force imposed at the friction interface.The actuation force is directly proportional to a load imposed on thehandle by a user.

The load on the handle is at its highest when the acceleration of thecleaner is at its highest which is at the end of each stroke, at theinstant of direction change. After a direction change, the accelerationof the cleaner typically drops to zero around mid-stroke and thenincreases in the opposite direction until the end of the stroke. Thismeans that the drive provides an appropriate amount of assistance, as itis needed. This also means that the drive is most effective when theunit is either always accelerating or always decelerating sinceacceleration or deceleration induces a load on the reciprocating handlewhich, in turn, imposes an actuation force at the friction interface. Incontrast, the user of a wet extractor typically desires to operate theunit at a slower, more controlled, preferably constant pace to uniformlyapply and then extract as much cleaning solution as possible.

If a friction drive mechanism such as that just described is employedfor a wet extractor application, the drive provides assistance upon thechange of direction, but when the user tries to obtain a controlledconstant linear velocity, the imposed force at the handle goes toapproximately zero (constant velocity means zero acceleration) and powerassist is lost. When power assist is lost, the user must impose moreforce on the handle to push the cleaner forward. This causes the clutchto engage and power assist is restored, but as the user continues toattempt control of the pace of the unit, power assist is again lost anda cycle of jerky motion and/or very minimal power assist ensues. Inorder to address this problem, a wet extractor drive should preferablyoperate the extractor independently of the magnitude of the actuationforce and yet still provide good power assist and response to userattempts to change the direction of motion.

The present invention contemplates a drive mechanism that reduces theamount of effort (force) required by the user to propel a wet extractorforward and back. The present invention addresses issues that arise fromattempting to drive an appliance on a wet surface such as loss oftraction and the interaction of the drive unit with the cleaningsolution. The contemplated drive system accomplishes this task in amanner that does not compromise the nature of the motion associated witha wet extractor. Specifically, the motion of a wet extractor ischaracterized by relatively slow, approximately constant velocityforward and rearward linear strokes of relatively long length (comparedto the typically shorter strokes of an upright vacuum cleaner).

Furthermore, the present invention contemplates a drive mechanism thatprovides more force to operate than an upright vacuum cleaner drive toovercome resistance caused by a high suction at the nozzle, baseconstruction (specifically the base length), and, in many cases, a lackof forward support wheels. The present invention also provides benefitby operating the cleaner at an appropriate speed for effective wetextraction, helping to reduce operator-induced inefficiencies.

Still further, the present invention contemplates a drive mechanism thatovercomes challenges associated with the operation of the extractor on awet surface such as a loss of traction and an interaction of the driveunit with cleaning solution which can include the infiltration of thesolution into the drive unit and a chemical interaction of the solutionwith materials of the drive unit.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, an uprightcleaning device is provided, comprising an upper assembly to which anactuator for receiving a user input is mounted, a base assembly to whichthe upper assembly is pivotally mounted, a rear wheel mounted to thebase assembly, configured to support the rear portion of the baseassembly, and a drive mechanism located in the base assembly. The drivemechanism has its major diameter in contact with a surface to becleaned, and the drive mechanism is configured to operate at one of:full speed in one direction, no speed and full speed in the oppositedirection, according to the relative position of the actuator.

In accordance with another aspect of the present invention, aself-propelled upright cleaning device is provided, comprising a nozzlebase, an upper housing section pivotally mounted to the nozzle base, ahandle actuator, a wheel for supporting the nozzle base, and a drivemechanism located in the nozzle base and having its major diameter incontact with a surface to be cleaned. The handle actuator for receivinga user input is mounted on the upper housing section. The drivemechanism comprises a stationary shaft, a stationary armature mounted onthe shaft, a tubular motor housing rotatably mounted on the shaft, and aplurality of magnets mounted to an inner face of the tubular motorhousing and spaced from the armature.

In accordance with yet another aspect of the present invention, aself-propelled upright cleaning device is provided, comprising a nozzlebase, an upper housing section pivotally mounted to the nozzle base, ahandle actuator for receiving a user input, and a drive mechanism. Thehandle actuator is mounted on the upper housing section. The drivemechanism is located in the nozzle base and has its major diameter incontact with the surface to be cleaned. The drive mechanism comprises arotating motor shaft, a rotating armature mounted on the shaft, astationary motor housing encircling at least a portion of the rotatingshaft, a sun gear mounted on at least one end of the motor shaft, aplanetary gear train comprising at least one planet gear engaging thesun gear, and a ring gear engaging the at least one planet gear. Thering gear is connected to a sleeve comprising a driven surface of thedrive mechanism.

In accordance with still another aspect of the present invention, amethod of propelling an upright cleaning device is provided, comprisingthe steps of sensing a user input from a handle actuator, operating adrive mechanism located in a base assembly, the drive mechanism havingits major diameter in contact with a surface to be cleaned, wherein thedrive mechanism is configured to operate at one of: full speed in onedirection, no speed and full speed in the opposite direction, accordingto sensed user input.

The advantages of the present invention will be readily apparent tothose skilled in the art, upon a reading of the following disclosure anda review of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in conjunction with accompanying drawings.The drawings are for purposes of illustrating exemplary embodiments ofthe invention and are not to be construed as limiting the invention tosuch embodiments. It is understood that the invention may take form invarious components and arrangement of components and in various stepsand arrangement of steps beyond those provided in the drawings andassociated description.

FIG. 1 is a perspective view of a first exemplary appliance, in the formof a vacuum cleaner with a drive mechanism, in the form of a wheel,according to the present invention being exploded out from it;

FIG. 2 is a perspective view of a bottom face of a nozzle base of thevacuum cleaner of FIG. 1 employing the drive mechanism of the presentinvention;

FIG. 3 is a perspective view from an upper side thereof of the nozzlebase of FIG. 2 with a top wall removed for clarity;

FIG. 4 is an exploded perspective view of a drive wheel assemblyaccording to a first embodiment of the present invention;

FIG. 5 is an enlarged partially assembled perspective view of the drivewheel assembly of FIG. 4;

FIG. 6 is a fully assembled front elevational view of the drive wheelassembly of FIGS. 4 and 5 in a reversed orientation;

FIG. 7 is a sectional view of the drive wheel assembly of FIG. 6;

FIG. 8A is an end elevational of the drive wheel assembly of FIG. 6showing heat dissipating fins;

FIG. 8B is a greatly enlarged view of a portion of FIG. 8A showing andmotor lead openings;

FIG. 9 is a perspective view of an armature suitable for incorporationinto motors used in drive wheel assemblies according to the presentinvention;

FIG. 10 is an elevation view in cutaway of a handle portion of theappliance of FIG. 1;

FIG. 11 is a functional block diagram of a first speed regulatingmechanism suitable to control the drive wheel assembly according to thepresent invention;

FIG. 12 is a functional block diagram of a second speed regulatingmechanism suitable to control the drive wheel assembly according to thepresent invention;

FIG. 13 is an exploded perspective view of a drive wheel assemblyaccording to a second embodiment of the present invention

FIG. 14A is a first sectional view of the drive wheel assembly of FIG.13;

FIG. 14B is a second, reversed, sectional view of the drive wheelassembly of FIG. 13 and,

FIG. 15 is a perspective view of a second exemplary appliance, in theform of a carpet extractor, with a drive mechanism, in the form of adrive wheel, according to the present invention being exploded out fromit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a self-propelled appliance 10 includes a baseportion 12 and a handle portion 14. Typically, the base portion 12includes a means such as a drive wheel 16 (shown exploded away from thebase portion 12) for propelling the appliance 10. Additionally, the baseportion 12 may provide or house implements or actuators for performingthe function of the appliance 10. While the invention is described asbeing used in connection with an upright vacuum cleaner, it should beapparent that the invention could also be employed in a carpetextractor, or a similar electrically powered home appliance. However,the invention could also be used with outdoor appliances, such aslawnmowers, snowblowers, or the like.

For example, where the appliance 10 is a vacuum cleaner the handleportion can include a filter chamber 18, and the base portion 12 may bea nozzle base. In addition to housing a means 16 for propulsion, thenozzle base includes a nozzle 20 through which dirt laden air isentrained. Dirt is removed from the air stream and collected in a bag,dirt separation chamber, or dirt cup of the filter chamber 18.Additionally, the nozzle base may include other implements for enhancingthe functionality and usability of the vacuum cleaner. For example, thenozzle base may house a brushroll 22 and additional wheels 23, as shownin FIG. 2, for improving the cleaning ability and maneuverability of thevacuum cleaner 18. Furthermore, the nozzle base may house power suppliesand control circuitry. Alternatively, power supplies and controlcircuitry may be located in other portions of the vacuum cleaner.

The handle portion 14 can be pivotally mounted on the base portion andprovides a means for an operator to direct the operation of theappliance 10. For example, the handle portion 14 may be used to steer ordirect the appliance 10. Additionally, the handle portion 14 may includecontrol elements.

The base portion 12 is configured such that drive wheel 16 has its majordiameter in contact with the ground when in an operational mode so as toexert a propelling force on the ground when signaled by an actuator 24via input from a user. The actuator is mounted on a handle 26 extendingfrom an upper housing section 28 of the handle portion 14. Theadditional wheels 23 on the nozzle base, which can be casters, allow theappliance to roll on the subjacent floor surface.

With reference now to FIG. 2, the base portion comprises a housing 30 onwhich the one or more wheels or casters 23 as well as height positioningwheels 32 are mounted. Also provided is the drive wheel 16 which ispositioned rearwardly of the brushroll 22 mounted in a brushroll chamber36 of the home appliance and before the rear casters 23 thereof. Thedrive wheel can be mounted to an intermediate plate 38 with theintermediate plate, in turn, being mounted to the housing 30. The wheel16 transmits torque to the subjacent support surface, be it carpeting ora hard surface, through a tread/ground interface thereby reducing theeffort required by the operator to propel the appliance. As shown inFIG. 3, the brushroll 22 can be powered by a separate brushroll motor40, via a conventional belt (not illustrated).

With reference now to FIG. 4, the drive wheel 16 can comprise areversible drive assembly 42. The drive assembly 42 in this embodimentis best characterized as a powered wheel. The assembly is essentially abrushless DC motor distinguished from typical brushless DC motors by thefact that a shaft 44 and an armature 46 are held stationary while a setof magnets 48 and a motor housing 50 rotate around the armature 46. Thisallows for a fairly compact design. A traction surface 52, in the formof two tread sleeves 53, can be applied to the motor housing 50 directlyand the motor, therefore, doubles as a wheel. To this end, the motorhousing 50 can include a steel motor tube.

With reference now to FIG. 5, motor end caps 54 can be rotatably mountedto the stationary shaft 44 by means of ball bearings 56. The bearings 56are mounted into bearing insulators 58 which are in turn mounted intoend caps 54. A rotary shaft/lip seal 60 can be provided around the shaft44, between the shaft 44 and the end cap 54. As shown in FIG. 7, theshaft 44 can be hollowed at one end to provide a channel 62 in the shaft44 to receive a shaft seal/strain relief 64 through which motor leads 66are routed into the channel 62 and through a connection block/shaft seal68 fitted in an opening 70 on the shaft surface into the internalchannel 62. Further, a non-reactive material can be used for the treadsleeves 53 in order to prevent chemical interaction between the cleaningsolution and the drive mechanism.

If desired, the motor end caps 54 can be constructed of aluminum andinsulated on their inner surfaces all around. The end caps 54 areinsulated from the bearings 56 by the insulators 58. The outer treadsleeves 53 can be made of a suitable conventional polymer and pressed onthe housing 50 with adhesive enabling the motor to double as a wheel. Asshown with reference to FIG. 6, the tread sleeves form a joint 72 in asurface tread pattern 74. With reference to FIG. 7, end caps 54 can beformed with heat dissipating fins 76.

The armature 46 further comprises coils 78 wound on laminations 80forming the armature yoke. With reference to FIGS. 7 and 9, the armature46 can include three Hall effect digital position sensors 82 (only oneshown). Each Hall effect position sensor 82 is located in the center ofthe armature 46 axially in a wider slot opening 84 with the Hallposition sensor 82 being flush with the outside diameter of the armature46. Furthermore, the three Hall position sensors 82 can be located inthree adjacent armature slots 86 with all three sensors positioned inlike manner with respect to the respective armature slot 86 and armature46. The Hall position sensors 82 can be secured in their respective slotopenings 84 with high temperature epoxy. Hall leads 88 extend from eachof Hall position sensors 82 out of one end of the armature 46 and belowthe outside diameter of the armature 46. The three leads from each ofthe Hall position sensors 82 provide for interconnection to theremaining Hall position sensors 82.

FIG. 8A shows the depth of the traction surface 52 formed on the driveassembly 42 by the tread sleeves 53. It also shows that the heatdissipating fins 76 on the motor end caps 54 are concentric with eachother and are separated by grooves 89. With reference now to FIG. 8B,shaft seal/strain relief 64 is provided with Hall lead openings 90through which Hall leads 88, of motor leads 66, exit the motor 42. Theshaft seal/strain relief 64 is also provided with power lead openings 92through which the remaining leads of motor leads 66 exit the motor 42.

With reference again to FIG. 1, the handle-mounted actuator 24 providesa means for an operator to direct the movement of the appliance 10. Forexample, the actuator 24 may be used to grasp the appliance 10 and tosteer or direct its movement. Additionally, the actuator 24 may includecontrol elements.

For example, with reference to FIG. 10, the actuator 24 may include ameans 100 for determining a desired drive effort for the means ofself-propulsion. For example, the means 100 for determining a desireddrive effort includes a first magnet 102, a second magnet 104 and ameans for sensing a magnetic field such as, for example, a Hall-effectsensor 106 and sensor leads 107. The actuator 24 also includes means 108for changing a relative position of the magnets and Hall-effect sensor.For example, the means 108 for changing the relative position of themagnets 102,104 and Hall-effect sensor 106 can include the handleportion 26, including a handle upper half 110 and a handle lower half112, and the actuator 24 can include a slide upper half 114 and a slidelower half 116. Such upper and lower halves 114,116 can form a tubeslidably mounted to the handle 26. The handle 26 is adapted or sized andshaped to be slidably received within the actuator 24. The magnets102,104 can be attached to magnet mounting surfaces 118 of the slideupper half 114. Fasteners, such as first and second slide screws120,121, can be used to secure the slide upper half 114 and slide lowerhalf 116 together. The handle upper half 110 and handle lower half 112are similarly secured together with fasteners such as handle screws 122.

When assembled, the Hall-effect sensor 106 can be disposed between likepoles of the magnets 102,104. For example, the Hall-effect sensor 106can be situated between a north pole 124 of the first magnet 102 and anorth pole 126 of the second magnet 104. This arrangement of the magnets102,104 provides a null in a magnetic field between the magnets 102,104and magnetic field lines of steadily increasing intensity as a relativeposition of a measurement point is brought closer to either of themagnets 102,104. Furthermore, due to this arrangement, lines of forceemanating from the like poles 124,126 are in opposite directions.

The slide screws 120,121 also secure the slide upper half 114 and slidelower half 116 to a center section of a self-centering resilient member128. The resilient member 128 is secured at each end to upper slidepartitions 130 and lower slide partitions 132. As mentioned above, thehandle 26 is adapted to be slidably received within the actuator 24. Thehandle 26 constrains the actuator 24 from lateral or twisting motions.However, the handle 26 can be slid into and out of the actuator 24,within the limits imposed by the resilient member 128, and thepartitions 130,132.

For example, the user may direct the appliance 10 to move forward orbackward by applying a pulling or a pushing force on the actuator 24. Inso doing, the user would move the handle 26 in a forward or backwarddirection. This urges the handle 26 into or out of the actuator 24. Asthe user pushes the handle 26 into the actuator 24, the second magnet104 is urged closer to the Hall-effect sensor 106 and the first magnet102 is moved further away. The Hall-effect sensor 106 senses anincreased magnetic field in a first direction and produces an electricsignal indicative thereof.

Similarly, if the user pulls the handle 26 out of the actuator 24, thesecond magnet 104 is moved away from the Hall-effect sensor 106, and thefirst magnet 102 is urged toward the Hall-effect sensor 106. TheHall-effect sensor 106 senses first a reduction in magnetic fieldstrength and then an increase in magnetic field strength in a seconddirection. The signal generated by the Hall-effect sensor 106 changes inconcert with these sensed changes in the magnetic field. The user movesthe handle 26 into or out of the actuator 24 according to a desireddrive effort. Therefore, the signal produced is indicative of a desireddrive effort.

As the user moves the handle 26 into or out of the actuator 24, portionsof the resilient member 128 are compressed while other portions arestretched by movements of the second slide screw 121. Therefore,restorative potential energy is stored in the resilient member 128. Ifthe user should release the actuator 24, the energy stored in theresilient member 128 returns the second slide screw 121 and, therefore,the handle 26 and the magnets 102,104 to the neutral position.

In the neutral position, the Hall-effect sensor 106 is locatedapproximately equidistantly between the magnets 102,104 in a nullbetween their respective magnetic fields. The signal from theHall-effect sensor 106 indicates this neutral magnetic field therebyproviding an indication that the desired drive effort is zero.

While the resilient member 128 in the illustrated embodiment can be madeof a resilient polymer, the resilient member 128 can also be made ofother known resilient materials. For example, a resilient member can befashioned from two wound wire springs joined together to provide acentral aperture between them and the loops for receiving the secondslide screw 122 and other mounting screws as necessary.

With reference now to FIG. 11, electrical signals to the armatureassembly 46 via motor leads 66 can be provided from a power source 140through a speed adjusting circuit 142. Alternately, with reference toFIG. 12, a sensor assembly 144, can be provided, for calculating aposition of the motor housing 50 relative to the armature 46. Forexample, the above-described Hall sensors 82 can provide positioninformation via Hall leads 88 of motor leads 66 to the speed adjustingcircuit 142, which permits selection of the proper commutated signal tobe sent along leads 66 to the armature 46. The sensor assembly 144 may,alternately, include an optical type sensor configured to detectrotations of the housing. While the speed adjusting circuit 142 isillustrated as being located outside of the wheel assembly 42, thecircuitry could alternately be placed within the wheel assembly 42 if sodesired.

Moreover, the speed adjusting circuit or device 142 can incorporatevarious functional capabilities such as constant brushroll speedmaintenance; overload protection stopping brushroll rotation; reversebrushroll operation easing, for example, backward movement of the vacuumcleaner; and variable brushroll rotation depending on floor surface,e.g. no rotation on tile, wood and delicate floor coverings, and fastrotation for heavy duty carpeting or especially dirty environments.

Another embodiment of a drive wheel assembly of the present invention isdepicted in FIGS. 13-14. In this embodiment, as shown in FIG. 14A, amotor 150 comprises a brushless DC motor, however, the motor is moretypical in that a shaft 152 and an armature 154 rotate while a set ofmagnets 156 and a motor housing 158 remain stationary. As shown in FIG.13, the shaft 152 is outfitted with a sun gear 160 on at least one end(spur or helical type, either integral with the shaft or mounted on theshaft) for input into a planetary gear train 161, including severalplanet gears 162, of at least one stage. Each of the planet gears 162 ismounted on a mount plate 164 connected to the motor housing 158. Theplanet gears 162 mesh with a ring gear 166 that is either integral withor mounted and fixed to an inner surface 167 of a sleeve 168. The sleeve168 is rotatably mounted on bearings 170 and 172 positioned on the motorhousing 158. Bearings 174 and 175 mount a pair of motor housing endplates 176 and 177 on the shaft 152. The sleeve 168 can be provided witha tread surface for engaging the surface to be cleaned.

The reduction provided by the gear train allows for a more common,higher speed, lower torque motor that provides cost and availabilityadvantages relative to the above-described stationary shaft motors.Control and actuation methods similar to those used for the firstembodiment can be employed to direct the movement of the appliance, suchas a vacuum cleaner or the like.

Another appliance in which the drive mechanism of the present inventioncan be used is a carpet extractor. For ease of appreciation of thisembodiment, like components are identified by like numerals with aprimed (′) suffix and new components are identified by new numerals.

With reference now to FIG. 15, the appliance can be a carpet extractor,as opposed to a vacuum cleaner. As before, the position of theHall-effect sensor with respect to the magnets determines the outputvoltage from the Hall-effect sensor. This output voltage is interpretedby a speed adjusting circuit and translated to an appropriate outputspeed and direction for the motor. For example, if the excitationvoltage to the Hall-effect sensor is 5 VDC then a Hall-effect sensorthat outputs 2.5 VDC when positioned exactly midway between the magnetscan be used. With such a construction, ranges from 1 VDC to 4 VDC, atthe extremes of travel of the actuator 24′ with respect to the handle26′, would be seen. In this exemplary arrangement, 1 to 2 VDCcorresponds to full speed in one direction, 2 to 3 VDC corresponds to ano speed, stationary position, and 3 to 4 VDC corresponds to full speedin the opposite direction. While one possible arrangement is disclosed,it should be appreciated that other arrangements of the Hall-effectactuation structure are also within the scope of the instant disclosure.

In an extractor application, a control algorithm can be adapted to rampup the speed of the drive motor to avoid jerky or abrupt directionchanges. This method addresses the issues associated with the slowconstant velocity nature of an extractor's motion. The output speed isthe same through a fairly large range of travel toward either extreme ofthe actuator 24′ position. This yields the same output speed for varyinglevels of input at the actuator 24′ yet still accommodates the user'sdesire to change direction. Thus, the constant, controlled speed desiredfor an extractor is attained and further optimized for efficientextraction.

With continuing reference to FIG. 15, a self-propelled carpet extractor180 includes a base portion 182 and a handle portion 14′. The baseportion 182 includes the above-described drive wheel 16′ (shown removedfrom the base portion 182) for propelling the self-propelled carpetextractor 180. Additionally, the base portion 182 houses implements oractuators for performing the function of the carpet extractor 180.

For example, the base portion 182 may include a cleaning solutiondispensing means (not shown). In addition to housing the drive wheel 16′for propulsion and a means for dispensing cleaning solution, the nozzlebase portion 182 includes a nozzle 186 through which dirt laden cleaningsolution is entrained. Dirt laden solution is removed from the nozzleand collected in a collection chamber, or other portion of the carpetextractor 180. Additionally, the nozzle base portion 182 may includeother implements for enhancing the functionality and usability of thecarpet extractor 180. For example, the nozzle base may house brushes,beater bars and additional wheels 188 for improving the cleaning abilityand maneuverability of the carpet extractor 180. Furthermore, the baseportion 182 may house power supplies and control circuitry.Alternatively, power supplies and control circuitry may be located inother portions of the carpet extractor 180. As described above, thehandle 14′ provides a means for an operator to direct the operation ofthe carpet extractor 180.

A change in motor direction can be accomplished via the use of an on offon rocker style switch input into the control electronics, if sodesired. The switch can be actuated via the use of a reciprocatinghandle as illustrated in FIG. 10. Design elements used in the previousembodiments to address issues such as solution infiltration into thedrive assembly and solution interaction with the drive assembly and thetread can also be incorporated in the embodiment of FIG. 15.

With the present invention, a reduced force is required by a user topropel the carpet extractor forward and back. Also, traction is not lostby the drive mechanism on a wet surface. In addition, the specificnature of motion of a wet extractor, characterized by relatively slowforward and rearward linear strokes, is not compromised by the drivemechanism. Rather, control and activation methods similar to those usedfor the embodiment shown in FIGS. 1-10 can be employed to regulate themovement of the carpet extractor. Moreover, operator inefficiencies arereduced by operating the carpet extractor at an appropriate speed foreffective wet extraction.

The invention has been described with reference to several preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding specification. It isintended that the invention be construed as including all suchmodifications and alterations insofar as they fall within the scope ofthe appended claims and equivalents thereof.

1. An upright cleaning device comprising: an actuator for receiving auser input; an upper assembly to which the actuator is mounted; a baseassembly, wherein the upper assembly is pivotally mounted to the baseassembly; a rear wheel, mounted to the base assembly, configured tosupport the rear portion of the base assembly; and a drive mechanismlocated in the base assembly having its major diameter in contact with asurface to be cleaned wherein the drive mechanism is configured tooperate at one of: full speed in one direction, no speed and full speedin the opposite direction, according to the relative position of theactuator.
 2. The device of claim 1, wherein the actuator comprises: ahandle slidably mounted to an upper portion of the upper assembly, firstand second spaced apart magnets fixedly mounted to the handle on an axisparallel to the longitudinal axis of the handle; a Hall-effect sensorfixedly mounted in the upper portion of the upper assembly such that thesensor is positioned: approximately midway between the first and secondmagnets when no user input is applied to the handle, in close proximityto the second magnet when a forward input force is applied by the user,and in close proximity to the first magnet when an opposite input forceis applied by the user.
 3. The device of claim 2, wherein theHall-effect sensor produces: an excitation voltage of 2 to 3 VDC when nouser input is applied to the handle structure; an excitation voltage of1 to 2 VDC when a first input force is applied by the user; and anexcitation voltage of 3 to 4 VDC when a second input force is applied bythe user.
 4. The device of claim 2, further comprising: a controllerwhich selectively powers the drive assembly inducing one of a constantspeed forward rotational motion and a constant speed backward rotationalmotion according to an excitation voltage produced by the Hall-effectsensor.
 5. The device of claim 1, wherein the drive mechanism comprisesa reversible wheel assembly including: a stationary shaft; a stationaryarmature mounted on the stationary shaft; a tubular motor housingencircling at least a portion of the stationary shaft; and a pluralityof magnets mounted to an inner portion of the tubular motor housingbetween the armature and the motor housing.
 6. The device of claim 5,the armature further including: a plurality of Hall-effect sensors forsensing a position of the armature, each sensor mounted in a respectivearmature slot approximately flush with the outside diameter of thearmature.
 7. The device of claim 5, the reversible wheel assemblyfurther including: first and second bearings mounted on the stationaryshaft.
 8. The device of claim 5, the reversible wheel assembly furtherincluding: first and second motor end caps located at respective ends ofthe motor housing wherein each end cap is mounted on and supported byone of the first and second bearings.
 9. The device of claim 8, whereinthe end caps are constructed with heat dissipating fins on their outersurfaces.
 10. The device of claim 8, further including: first and secondlip seals incorporated into the motor end caps and encircling thestationary shaft.
 11. The device of claim 5, further comprising a wheeltread secured to and covering the motor housing.
 12. The device of claim11, wherein the wheel tread comprises two molded polymer tread end capshaving a molded surface tread pattern on an outer cylindrical portion ofthe end caps.
 13. A self-propelled upright cleaning device comprising: anozzle base; an upper housing section pivotally mounted to the nozzlebase; a handle actuator, for receiving a user input, mounted on theupper housing section; a wheel for supporting the nozzle base; and adrive mechanism located in the nozzle base and having its major diameterin contact with a surface to be cleaned wherein the drive mechanismcomprises: a stationary shaft, a stationary armature mounted on saidshaft, a tubular motor housing rotatably mounted on said shaft, and aplurality of magnets mounted to an inner face of the tubular motorhousing and spaced from said armature.
 14. The device of claim 13, thearmature further including: a plurality of Hall-effect sensors forsensing a position of the armature, each sensor mounted in a respectivearmature slot approximately flush with the outside diameter of thearmature.
 15. The device of claim 13 wherein said drive mechanismfurther comprises a traction surface secured to an outer periphery ofsaid tubular motor housing.
 16. The device of claim 13 wherein saiddrive mechanism further comprises first and second bearings mounted onthe stationary shaft for rotatably mounting the tubular motor housing.17. The device of claim 16 further comprising first and second motor endcaps located at respective ends of the motor housing, wherein each endcap is mounted on and supported by one of the first and second bearings.18. The device of claim 17 further comprising first and second lip sealswhich are incorporated into a respective one of the first and secondmotor end caps and encircle the stationary shaft.
 19. A self-propelledupright cleaning device comprising: a nozzle base, an upper housingsection pivotally mounted to the nozzle base; a handle actuator forreceiving user input, said handle actuator being mounted on the upperhousing section; and, a drive mechanism located in the nozzle base andhaving its major diameter in contact with the surface to be cleaned,wherein the drive mechanism comprises: a rotating motor shaft, arotating armature mounted on said shaft, a stationary motor housingencircling at least a portion of the rotating shaft, a sun gear mountedon at least one end of the motor shaft, a planetary gear traincomprising at least one planet gear engaging said sun gear; and a ringgear engaging said at least one planet gear, said ring gear beingconnected to a sleeve comprising a driven surface of said drivemechanism.
 20. The device of claim 19, the armature further including: aplurality of Hall-effect sensors for sensing a position of the armature,each sensor mounted in a respective armature slot approximately flushwith the outside diameter of the armature.
 21. The device of claim 19further comprising a wheel tread concentrically located with respect tothe motor shaft wherein said wheel tread is mounted on said sleeve. 22.The device of claim 21 further comprising first and second bearingsmounted on the motor shaft wherein the bearings support respective endsof said sleeve.
 23. The device of claim 19, wherein the sun gear isconnected to the motor shaft.
 24. The device of claim 19, wherein threespaced planet gears engage said sun gear.
 25. The device of claim 24,wherein the ring gear is of one piece with said sleeve.
 26. A method ofpropelling an upright cleaning device comprising: sensing a user inputfrom a handle actuator; operating a drive mechanism located in a baseassembly having its major diameter in contact with a surface to becleaned wherein the drive mechanism is configured to operate at one of:full speed in one direction, no speed and full speed in the oppositedirection, according to sensed user input.
 27. The method according toclaim 26, wherein the step of sensing a user input comprises: producinga first excitation voltage when no user input is applied to the handle;producing a second excitation voltage when a forward input force isapplied by the user; and producing a third excitation voltage when anopposite input force is applied by the user.
 28. The method according toclaim 27, wherein a Hall-effect sensor produces the first, second andthird excitation voltages according to the position of the Hall-effectsensor with respect to two fixed magnets mounted to a non-slidableportion of the handle wherein the Hall-effect sensor is mounted to aslidable portion of the handle.
 29. The method according to claim 28,wherein the first excitation voltage is in the range of 2 to 3 VDC, thesecond excitation voltage is in the range of 1 to 2 VDC, and the thirdexcitation voltage is in the range of 3 to 4 VDC.